A laboratory investigation was conducted to determine properties of five samples of 'oolitic ironstone' lateritic gravel aggregates which are relevant to their use as road construction materials. Measured values of physico-chemical, physico-mechanical as well as index properties and compaction characteristics are similar to those of other lateritic, gravels occurring in West Africa which are used in road pavement applications. These lateritic clayey gravels have good workability as engineering construction materials and are rated fair to good as road aggregates in terms of probable in-situ behaviour based on water absorption values. Relationships between maximum dry unit weight and optimum moisture content as well as those between California bearing ratio and some derived soil parameters such as grading modulus, plasticity product or plasticity modulus can be described using a third-order polynomial function. The maximum dry unit weight has a bimodal frequency distribution and can be predicted from logarithm to base 10 of compaction energy with fairly good accuracy.

This study is aimed at assessing the extent of leaf nutrient resorption efficiency during senescence of three species (Khaya. senegalensis, Syzygium cumini and Pongomia glabra) in the Sudano-sahelian region of Nigeria. The species were selected from grooves of trees found within Maiduguri metropolis. Three leaf samples at different developmental stages (young, matured and senescence leaves) each were collected from the selected species. Each sample was then analysed for nutrient contents. C content ranged from 39.79% in K. senegalensis, 43.89% in S. cumini to 41.59% in P. glabra. Matured leaves of S. cumini have the highest K content with mean value of 9.08mg/kg, whereas young leaves of K. senegalensis and P. glasbra were the highest with mean values of 8.68mg/kg and 8.45mg/kg respectively. There was a significant decrease in K. content during senescence in S. cumini. Senescent leaves of K. senegalensis and P. glasbra have higher Ca content with 1.06mg/kg and 0.81mg/kg, respectively while matured leaves of S. cumini have the highest mean Ca content (0.82mg/kg). Young leaves have the highest mean values of S content in all the leaves of the three species. S declines significantly from matured to senescent in K. senegalensis. Young leaves of S. cumini and P. glabra, and senescent leaves of K. senegalensis have the highest mean values of Mg with 0.29mg/kg, 0.39mg/kg and 0.31mg/kg, respectively. Leaf P content is highest in matured leaves of K. senegalensis, S. cumini and P. glabra with mean values of 0.06mg/kg, 0.04mg/kg and 0.06mg/kg respectively and decreases during senescent. However, the decrease was only significant in P. glabra. The highest mean value for N is recorded in the young leaves of K. senegalensis with 0.04mg/kg, but it is highest in senescent leaves of S. cumini with 0.06mg/kg and P. glabra with 0.17mg/kg